Method of making printing plates



April 2, 1929. w. M. KELLY 1,707,729

METHOD OF MAKING PRINTING PLATES Filed Dec. 27, 1926 E. -1 .sa 1 I 5y. m

l: /l/ MY" Patented Apr. 2, 1929.

UNITE-D s'ia'rtzst WILLIAM M. KELLY, 0l' WEBTIIELD, NEW m.

METHOD 0F MAKING PRINTING PLATES.

.ippiicaaon sied December a7, 192s. semina. 157m.

The present invention relates to an improved method of making printing plates and to the plate as an article of manufacture. A

One of the objects of the invention is to make a printing plate consisting of a phenolie condensation product with make-ready incorporated therein. d

Another object of the inventiony is to provide a process whereby a permanent starting plate may-be prepared by applying makeplate;

ready thereto, and whereby any number o `printing plates may be made from such made- 'ready starting plate without injuring the original design or applied make-ready.

Another object of the invention is to provide a process for making printing plates with make-ready incorporated therein by treating originals such as made by photoengiavers, or duplicates from such originals, thus creating a master plate.

Another object of the invention is to provide a process that can be carried out by the i `curved printing plate.

printer in his ownshop.

Another object of the invention is to provide .a process whereby a final printing plate may be obtained more rapidly than heretofore and with less labor.

Another object of the invention is to provide a process for making a curved plate suitable for use on printing cylinders.

Another object is to provide a simplified process of producing printing plates.

In one of the best known processes of anplying make-ready to printing plates, t-he starting plate is a relief plate as it comes from the electrotyper. The process of the present invention is not limited to starting with such a relief plate but on the contrary, any original may be employed.

In this well known prior process, the final I printing plate secured is the plate with which the process started modified by the steps of the process. On large edition printing the same forms are duplicated many times. labor of applying the make-ready is repeated with each plate treated. According to the present invention. the final plate secured is a different plate from the starting plate and any numberA of these final plates may be made from' the starting or master plate.

'Other objects and features of novelty will be apparent from the description taken in connection with the accompanying drawings, in which Fig. lis a sectional elevation of a starting The plate employed inthe resentprocess, with the make-readyfap lie thereto, it being undei-stood that in t is and the other figures of the drawings, the thickness of the makeready and the plates themselves is greatly exag erated; i

ig. 2 is a sectional elevation of an apparatus, such as the well-known electrotypers power press, for making the matrix-plate from the made-ready starting plate;

Fig. 3 1s a sectional elevation of the matrix- Fig. 4 is a sectional elevation of an apparatus, such as an electrot ers press, for making the final plate from t e matrix-plate;

Fig. 5 is a sectional elevation of the final plate;

Fig. 6 is a sectional elevation of an apparatus for making a curved matrix-plate;

Fig. 7 is a sectional elevation of'an a paratus for making a curved final plate fiom the matrix-plate; and

Fig. 8 is a sectional elevation of a final The final printing plate secured by the process of this invention can be made from almost any starting plate or original, such as a photo-engraving, a line plate, a halftone plate, an electrotype or a stereotype. In other words the process is not limited to starting with a second processor electro-plate. In this description and the claims, the plate with which the process starts will'be termed a starting plate, or original.

The first step of the process consists in applying make-ready to the startin plate 10. This may be done in any suitab e way, so that after an impression has been taken .in soft metal from the made-ready plate, the portions that require additional lprinting pressure will be the most deeply depressed in the soft metal impression. According to one method, several proofs are taken from the starting plate. The portions of the matter that require-additional pressure are out out, and t-hese cut out pieces indicated at 11,

12, 13 and 14, are applied to the back of the starting plate in register with the subject on the face of the plate, the face of the plate being indicated at 15. A suitable number of these cut o ut pieces are applied in this manner so that the required gradations will be secured when printing from the final plate. This made-ready plate may be termed the master-plate.

The next step consists in making an impression in the soft metal from the masterplate. For this purpose the face of the master-plate is placed in contact with a plate comprising three layers or laminas. The face of this plate is copper, say, of one-half thousandth thickness, so that the final printing plate will give the sharpest ossible dchnition and also so that the fina plate made from this plate may be released therefrom without pul1ing. The next layer 17 is of soft metal such as lead, and the backing layer 18 is a phenolic condensation product. The object of this backing is to fill in and support the lead to prevent its giving away under the pressure in the next step of the process.

As is well known, phenolic condensation products exist in three different conditions or stages. In the first stage they range from a fluid to a plastic state. In the second stage they have a consistency like that of hard wax. In the third stage, which is secured by heat or heat and pressure, the material is very hard and permanent. According to the present invention, the backing 18 is applied to the soft metal or lead layer 17, in the B condition. Thereafter, when the backed plate and the master-plate are pressed together, the heat necessary to change the phenolic condensation product to the C stage is supplied in any suitable manner.

The apparatus for, and method of', Inaking the impression in this backed plate, or matrix-plate as it is termed herein, is shown in Fig. 2. Any suitable apparatus for giving the desired pressure and heat may be emplo ed. The well known electrotypers press is i lustrated. As shown, it comprises a table 19 with a heating means such as the steam tubes 20 passing therethrough. The ram and guides therefor are shown at 21 and 22 respectively. The steel bearers to limit the squeeze or fix the thickness of the plate, are shown at 23. If necessary, in order to obtain the proper thickness of matrix-plate, steel filler plates 24 may be placed on the table 19. To secure the impression in the matrix plate, the starting plate is placed face up on the table 19 or filler piece 24, and then the copper-faced lead sheet is placed on the face of the starting plate and finally the phenolic condensation product 18 is applied to the back of the lead sheet. Then the ram 21 is operated to take an impression in the oopper-faced lead plate, the heat to change the phenolic condensation product to the C stage being supplied by means such as the steam tubes 20. The extent of downward movement of the ram 21 is limited by the bearers 23 so that the matrix-plate secured is of the proper thickness. The matrix-plate resulting from this step of the process is shown in section in Fig. 3.

The next step of the process consists in securing the final printing plate from the ma- When the final trix-plate. A press like that shown in Fig. 2 may be employed, the matrix-plate and final plate being arranged in the press as shown in Fig. 4. Thus the matrix-plate is placed face up on the table 19 or filler piece 24. Around the edges of' the matrix-plate and on the face thereof are placed the pieces 25 of magnetic metal for a purpose described hereinafter. The space above the face of the matrix-plate and between the bearers 23 is then filled with a phenolic condensation product in the plastic or B stage. If the matrix-plate is not thick enough, one or more of the filler plates 24 may be used to build it up to the required thickness. Now, the impression is taken by operating the ram 21 and applying heat as by means ofthe steam tubes 20.` The heat and pressure convert the phenolic condensation product into the hard C form. and the movement ofthe ram. and thus the thickness of the resulting plate. is limited by the bearers 23. The final printing plate secured, consisting of a phenolic condensation product, is shown in section in Fig. 5. In this manner any number of final printing plates 26 may be secured. If the matrixplate should become worn or defective, a new one can be made from the master plate.

In cooling and setting, the final plate may become slightly distorted, and may require treatment to square it up. If this is necessary the plate may be placed face down on grinding machine and the back ground to be truly flat. To aid in this operation the final plate may be provided with the strips of magnetic metal 25 embedded in the bearers or margins of .the plate 26. This magnetic metal is preferably disposed in the plate when the phenolic condensation product is in the B stage so that it is embedded in the plate at the marginal portions of the face thereof. plate is placed on a surface grinder equipped With a magnetic chuck, it will be held fiat on its face because of the magnetic metal inserts and thus its back can be ground truly flat.

In order that the magnetic metal pieces 25, or the faces of the portions of the plate in front of the pieces, shall be level with the highest portions ot' the plate, make-ready strips 40 may be applied to the original or starting plate.

Phenolic condensation products, in the C state. are somewhat brittle and in the process of printing the plate may become broken or Cracked. For the purpose of holding the pieces of the plate together, if it should become cracked, and preventing pieces from falling into the press, the final plate when in the B stage may be provided with a reinforcing means, such as a wire mesh or canvas 27.

If a final plate in curved form is to be secured, the steps of the process are as follows:

Prepare a master plate as shown in Fig. 1.

2.l Bend this plate to the desired curvature, the face of the plate being on the convex side.

3. Place this curved plate 30 face up on the curved table 31 of a' press of the type shown in Figs. 2 and 4. lf necessary, filler pieces 32 may be inserted between the back of the plate 30 and thc table 3l.' Now the material to form the matrix-plate is placed in position on the face of the master plate 30, as shown in Fig. 6. This plate consists of the copper facing 33, the lead layer 34 and the backing 35 of a phenolic condensation product. The ram 36 is now moved downwardly until it strikes the bearers 37 and heat is supplied as by the steam tubes 38. As a result the matrix plate is molded and the phenolic condensation product changed from the B to the C stage.

4. In the next step, the required amount of a phenolic condensation product in B stage is placed on the table 31 of a press of the same construction'as shown in Fig. 6 being disposed in a layer the edges of which contact with the bearers 37 of the press or molding machine. The matrix-plate is placed on top of thelayer of phenolic condensation product and if necessary one or more filler plates 39 are disposed between the matrix plate and the ram 36, as many of these filler plates being employed as are re uired to give the predetermined thickness o the final plate. The ram 36 of the press is now moved downwardly until limited by the bearers 37, heat being supplied in any suitable manner as by the steam tubes 38. Reinforcing means such` as wire mesh or canvas 27 is placed in the layer of phenolic condensation product for the purpose previously described.

The resulting final curved plate 41 is shown in section in Fig. 8.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is 1. The method of making printing plates, consisting in applying make-ready to an original, molding a matrix-plate capable of resisting pressure from said made-ready plate, and making by heat and pressure a printing plate of a phenolic condensation product from said matrix-plate, said printing plate thus having the make-ready incorporated therein.

2. The method of making printing plates, consistitng in applying make-ready to an original, placing a reinforced soft metal sheet against the face of said made-ready plate and taking an impression in relief by pressure, placing a phenolic condensation product on the face of said metal plate and subjecting the two to heat and pressure.

3. The method of making printing plates, consisting in applying make-ready to an original, making an impression in relief from said made-ready original in soft metal having a strengthening backilw consisting o f a. phenolic condensation )roduct and making a printing plate of a p ienolic condensation product from said impression.

4. The method of making printing plates, consisting in applying make-ready to an original, placing said made-ready plate, and a plate consisting of a copper-faced soft metal and a backing of a phenolic condensation product, in contact, subjecting said two plates to heat and pressure, and making a printing plate of a phenolic condensation product from said metal plato.

5. The method of making curved printing plates consisting in applying make ready to an original, bending said plate to the proper curvature, molding a curved matrix-plate from said made-ready original, and molding `a final curved plate from said matrix-plate.

6. The method of making curved printing plates consisting in applying make-ready to an original, bending said plate to the proper curvature, molding a curved matrix-plate from said made-ready original, and molding a final curved plate of a phenolic condensation product from said matrix-plate.

7. The method of making curved printing plates consisting in ap lying make-ready to an original, bending said plate to the proper curvature, molding a curved matrix-plate from said made-ready original, said matrix plate consisting of a soft metal having la copper facing and a backing of a phenolic condensation product, and molding a final curved plate from said matrix-plate.

8. rlhe method of making curved printing plates consisting in applying make-ready to an original, bending said plate to the proper curvature, molding a curved matrix-plate from said made-ready original, said matrixplate consisting of a soft metal having a copper facing and a backing of a phenolic condensation product, and molding a final curved plate of a phenolic condensation product from said matrix plate.

9. The method of making printing plates consisting in making a matrix-plate of reinforced soft metal with portions that are to print with the greatest pressure the most deeply depressed, and molding with pressure a final plate from said matrix-plate.

10. The method of making a printing plate, consisting in making a matrix-plate of soft metal having a strengthening backing, the portions that are to print with the greatest pressure being the most deeply depressed, and molding with pressure a iinal plate from said matrix-plate.

11. The method according to claim 12 wherein the backing is a phenolic condensation product.

12. The method according to claim 11 wherein the final plate is a phenolic condensation product.

13. The method of making a printing plate consisting in making a matrix-plate of reinforced sol't metal with the portions that are to print with the greatest pressure the most deeply depressed, and molding by heat and pressure a final plate of a phenolic condensation product from said matrix-plate.

14. 'Ihe method of making a printing plate, consisting in applying make-ready to an original, making a matrix-plate of soft metal with a strengthening backing from said made-ready plate, the portions that are to print With the greatest pressure being the most deeply depressed, and molding a final plate of a phenolic condensation product from said matrixlate.

15. A metal facing ha matrix-p ate consisting of a soft l the portions that are to ving condensation pr In testimony slgnature.

oduct. whereof I hereunto affix my WILLIAM M. KELLY. 

